Modified DRM+ signal generation algorithm with reduced crest factor

Abstract

To reduce the crest factor in the DRM+ system due to the limitations imposed by the standard the peak limiting method (clipping) and the window weighting method, which are based on signal distortion, are widely used. As a result of the application of these methods out-of-band emissions in the signal spectrum significantly increase. After filtering out-of-band emissions the effect of a repeated increase in the crest factor appears. In this regard, there is an urgent scientific and technical problem of finding the optimal method for filtering out-of-band emissions of the DRM+ signal. The purpose of this article is to analyze the existing methods for filtering out-of-band emissions in the process of reducing the crest factor in a DRM system, as well as choosing the optimal filtering algorithm after reducing the crest factor for DRM+ transmitters. A method for suppressing out-of-band emissions using a digital filter based on FFT / IFFT is considered. The modeling of the proposed algorithm for filtering the signal by the mask of out-of-band emissions is carried out. Comparative studies of the method of the standard filtering algorithm and the proposed algorithm are carried out; the high efficiency of the latter is shown. The results obtained will improve the efficiency of reducing the crest factor in broadcasting transmitters of the DRM + standard, thereby increasing their power efficiency.